[Dovecot] Design details of high performance dovecot cluster

Robert Schetterer rs at sys4.de
Fri Dec 6 13:12:44 EET 2013

Am 06.12.2013 11:28, schrieb JEHERUL:
> Dear All,
> Currently we are running a mail system for 10000 users each 2GB mailbox. At
> present we have 5 mail servers where users mailboxes are distributed almost
> uniformly. 

looks enough

We have a HP SAN Storage (HP EVA 6400) where mailboxes are
> stored. We partition the storage into five vg and each is mounted on the 5
> servers. We are using postfix and dovecot.
> The system was running fine but currently we  notices high IO load due to
> IMAP connection. So we are planning to build a dovecot cluster.

ident the io problem on the storage, give more info about  mailbox
format etc

perhaps read


> Please suggest some design for the dovecot cluster keeping in mind to our
> scenario. (If needed we can buy additional hardware like load balancer).

you should use loadbalancer, you dont have to buy it , something like
keepalived etc is enough, however you should use

http://wiki2.dovecot.org/Director with more servers

for an idea with loadbalancers look at


( sorry german only )

> With Thanks and Regards

at last
you have to give more info like dovecot version , config
logfiles , general setup

Best Regards
MfG Robert Schetterer

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